Some electronic cabinets store computer equipment such as circuit boards (e.g., processor boards, memory boards, networking boards, etc.), power supplies, disk drives, combinations thereof, and the like. A typical electronic cabinet has a fan assembly that moves air through an airflow pathway within the cabinet in order to remove heat generated by the equipment stored therein. Noise is a typical byproduct of the operation of the fan assembly. The amount of noise emanating from some fan assemblies, particularly from fan assemblies which include large fan motors or many fan motors, can be so substantial that the electronic cabinets storing those fan assemblies are not suitable for operating in an office environment.
Some businesses choose to locate electronic cabinets away from office areas in dedicated lab areas (e.g., separate rooms) so that the operation of the electronic cabinets does not interfere with the office areas. Often the lab areas provide a controlled environment (e.g., constant humidity and temperature, security, etc.) and provide convenient access to the cabinets (e.g., ceiling troughs and raised floors for power and network cables, space for adequate air circulation, etc.). Due to the large amount of noise typically emanating from the electronic cabinets in these areas, people who often spend a significant amount of time working in the vicinity (e.g., equipment operators, service technicians, etc.) typically wear earplugs or headphones to protect and preserve their hearing.
Proposed governmental regulations for limits on the allowable noise levels of machinery operating in both attended and unattended operating areas have forced designers of such equipment to develop machines that either generate less noise during operation or suppress any noise that is generated by the machines.
One electronic equipment manufacturer provides an electronic cabinet assembly having (i) a cabinet, (ii) a fan assembly located in the top of the cabinet, and (iii) a conventional noise muffling device that rests on top of the cabinet over the fan assembly in order to reduce noise emanating from the fan assembly. The noise muffling device is roughly a foot in height. The muffling device includes a grid of fiberglass padding and an outer steel housing that holds the grid over the fan assembly. A screened mesh retains the fiberglass in the grid configuration and prevents pieces of fiberglass from escaping into the air. The grid of fiberglass padding defines sets of flat sides which run parallel to the direction of the airflow pathway through the cabinet. When the fan assembly is in operation, some of the noise energy is absorbed by the grid of fiberglass thus reducing the amount of noise emanating from the cabinet.